1-Aminobenzene-2-sulfonic acid 2-Aminobenzenesulfonic acid 88-21-1 ANILINE-2-SULFONIC ACID Aniline-o-sulfonic acid Aniline-o-sulphonic acid Benzenesulfonic acid, 2-amino- Benzenesulfonic acid, o-amino- NSC147 Orthanilic acid o-Aminobenzenesulfonic acid o-Sulfanilic acid